Dan, K6KDK, wrote: > One of the reasons this is important is that there is really > no such thing as RF Gain any way in a DSP radio.
Good point. And this actually raises an interesting question regarding the naming of controls... >From my perspective, the SDR1K has, essentially, two gain controls. Conceptually, from the point of view of signal flow, I picture these two gains as "pre-agc gain" and "post-agc gain." That is, the gain applied to a signal *before* it's attenuated by AGC, and the gain applied to a signal *after* it's been attenuated by AGC. The post-agc gain control is called "AF Gain," and, intuitively, we all understand what it does, because we've all operated radios that have a knob called "AF Gain." In other words, any ham in the world can walk up to the SDR1K's console and immediately understand what the AF Gain control does, without having to read the manual. The SDR1K's pre-agc gain control is called "Max AGC Gain," and in earlier consoles this control was buried in the Setup menues. The problem with the name "Max AGC Gain", though, is that many hams might not know how to use this control without first reading the manual. It isn't obvious how it relates, or if it relates at all, to receiver controls that they're familiar with, nor is it clear how they should use it. What's interesting, though, is that if you look at the AGC code, it becomes quickly apparent that "Max AGC Gain" is *functionally* equivalent to the "RF Gain" control that hams are familiar with on non-SDR radios. That is, both set the maximum amount of gain that is applied to a signal before that signal is attenuated by AGC (i.e. pre-agc gain). The functional similarity between "Max AGC Gain" and the familiar "RF Gain" control raises an interesting question - is it better give a control a name that accurately represents what it does in the code (such as "Max AGC Gain") but that may be confusing to anyone who hasn't read the manual (or have a PHD in Gizmotronics), or to give the control a name that represents the control's function in terms that the user is familiar with and lends itself to an intuitive understanding of how to use the control? "Max AGC Gain" is more accurate from the point of view of the code itself, but (at least to me) "RF Gain" is more intuitive. Or, perhaps more importantly, if there was a control on the front panel labeled "Max AGC Gain," would this turn-off, rather than attract, potential buyers of the radio? I don't know the answer to these questions. Just wondering... - Jeff, K6JCA _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
